Bad luck continues - B&M diff cover

[BlackSheepRebel]

I'm working with the vendor to get this resolved, but before working all the way through that and getting a replacement, I wanted to fish for opinions...

Decided to service my rear diff this weekend. Got the Valvoline 75w-140 in the flex packs with the anti-slip additive included. This will be easy, right?

No problems getting the factory cover off. Decided to upgrade to the B&M cover since I've had good luck with B&M products in the past and this one isn't flat backed, has a magnetic drain plug, holds an extra 1/2 quarter of fluid, and looks decent. I've watched videos of it being swapped, and mostly had no problems other than needing to drop my sway bar and remove the bolt in one side of my panhard bar to be able to reach all the bolts. Not a big deal.

The problem came when torquing the fill plug. It's only 25lb/ft, and I used the same torque wrench and allen socket on all the other bolts on the cover without issue. The fill plug rounded off before even getting to 25lb/ft. WTH?

Given how long it took me to get my suspension dialed in, by now I've learned to laugh at myself so I was going to just leave it and use the factory drain plug next time. Turns out I can't do that either though, because the plug also has a slow leak even though I wrapped it with a couple layers of pipe thread tape per instructions. Not sure if it's tapped wrong or just can't get the right torque on it due to being rounded it off. Made me think, because the load bolts they provide were also very hard to thread in even after cleaning the threads with break clean and working them in/out a few times by hand. The bolts themselves had what looked like minor thread imperfections.

I'm willing to say this is my own stupidity (not sure why all the other bolts torqued just fine, and it rounded off completely not on one side or at an angle, my allen socket looks fine...so not 100% sure I could have wrenched better but maybe?) or even just a one-off...even good manufacturers have occasional lemons. Wondering if anyone else has used this diff cover and has good or bad experiences with it? I am talking to the vendor now about a swap, but if anyone has bad experiences to share I might just cut my losses and clean up and reuse the factory cover.

Thanks!

 

[Zoe Saldana]

You sure it wasn't 25 inch pounds?

 

[BlackSheepRebel]

Honestly had to go look since there's a mix of in/lb and ft/lb for this job, it's been one of those days!

The B&M instructions say:

Diff screws/bolts 15 ft-lbs
Load screws and lock nuts 5 ft-lbs
Fill & drain plugs 25-30 ft-lbs (I set these all to 25 to account for measurement error)

Pardon the highschool math for the in-lb conversion, didn't have my phone handy and I always triple check stuff like this:

 

[DanAR]

We’re the hex socket plugs SAE or metric? Hex so socket maybe not a tight fit?

 

[BlackSheepRebel]

Good questions... always the biggest fear with allens. It's SAE. 1/4 for the diff bolts and drain plug and 3/8 fill plug. Not sure why they couldn't have made the drain 3/8 as well... but it didn't wobble, still fits tight, and the same socket had no problem on the other 12 diff bolts (had to use it to remove everything).

Honestly knew this was debatable in the first place but went with the B&M for the magnetic drain plug and fact it's rounded like OEM (PPE is semi-rounded, but has "scrapers" I wasn't sure about).

Hard to believe quality metal would round off at 25 ft-lbs. Even if they send me a new cover, thinking really hard if I want to fear this on every change.

 

[Bigskyroadglide]

Doesn't your rear diff have a drain plug at the bottom of the diff and a fill plug at the top of the diff and in the rear cover, covered by a rubber plug?

Not certain I understand the advantage of this cover. Not saying anything bad, just trying to understand if there is an advantage. All the features you spoke about are available on the factory parts, except the additional half quart of fluid.

I mean the part visually looks good, but apparently maybe has some manufacturing issues or the torque amounts were described incorrectly. 25 to 30 inch lbs, is not alot whereas 25 to 30 ft lbs is a bunch in aluminum.

My opinion, bad machining

 

[Daw14]

I’ve been running a b@m rear cover like that for about four years now with no issues. I’ve changed fluid a couple times. It has fins to provide additional cooling , and aluminum helps disapate heat quicker than steel.

 

[Rebel4Mo]

I assume the fill plug is tapered pipe thread (NPT).
I know the instructions said 25 FT. pounds but I have never torqued a pipe thread fitting.
Seems pretty tight.

 

[Zoe Saldana]

It does seem like a lot, especially into Al.

I assume the fill plug is tapered pipe thread (NPT).
I know the instructions said 25 FT. pounds but I have never torqued a pipe thread fitting.
Seems pretty tight.

 

[Wild one]

Using a Torque Wrench on a pipe plug was your second mistake,first mistake was thinking that cover is any better then the OEM cover. Stick the OEM cover back on,and chalk it up to a lesson from the school of hard knocks

 

[mikeru]

Using a Torque Wrench on a pipe plug was your second mistake,first mistake was thinking that cover is any better then the OEM cover. Stick the OEM cover back on,and chalk it up to a lesson from the school of hard knocks

I agree with this. What were you trying to improve on with the B&M diff cover? These are the sorts of parts that the only thing they are good at is separating people from their money.

 

[Rebel4Mo]

The covers add bling under the trucks!

The stock cover on my '01 is 23 years old and keeps doing its job.
I have towed trailers for all those years and not having the extra fluid capacity has not been a problem.
The diff has 189K miles.

 

[Scottly]

Dare I ask, but did you use an American-made hex plug socket, or a chow mien socket? I used to run into this when I was a Snap-On dealer. People always scoffed at the price of my tools, but there are some things where our quality was far superior and cheap ones caused headaches...Allen keys/hex plug sockets were one of them...TORX were right behind them. Just sayin'...When the fit on the fastener is loosey-goosey, this crap happens.

 

[Sherman Bird]

I'm working with the vendor to get this resolved, but before working all the way through that and getting a replacement, I wanted to fish for opinions...

Decided to service my rear diff this weekend. Got the Valvoline 75w-140 in the flex packs with the anti-slip additive included. This will be easy, right?

No problems getting the factory cover off. Decided to upgrade to the B&M cover since I've had good luck with B&M products in the past and this one isn't flat backed, has a magnetic drain plug, holds an extra 1/2 quarter of fluid, and looks decent. I've watched videos of it being swapped, and mostly had no problems other than needing to drop my sway bar and remove the bolt in one side of my panhard bar to be able to reach all the bolts. Not a big deal.

The problem came when torquing the fill plug. It's only 25lb/ft, and I used the same torque wrench and allen socket on all the other bolts on the cover without issue. The fill plug rounded off before even getting to 25lb/ft. WTH?

Given how long it took me to get my suspension dialed in, by now I've learned to laugh at myself so I was going to just leave it and use the factory drain plug next time. Turns out I can't do that either though, because the plug also has a slow leak even though I wrapped it with a couple layers of pipe thread tape per instructions. Not sure if it's tapped wrong or just can't get the right torque on it due to being rounded it off. Made me think, because the load bolts they provide were also very hard to thread in even after cleaning the threads with break clean and working them in/out a few times by hand. The bolts themselves had what looked like minor thread imperfections.

I'm willing to say this is my own stupidity (not sure why all the other bolts torqued just fine, and it rounded off completely not on one side or at an angle, my allen socket looks fine...so not 100% sure I could have wrenched better but maybe?) or even just a one-off...even good manufacturers have occasional lemons. Wondering if anyone else has used this diff cover and has good or bad experiences with it? I am talking to the vendor now about a swap, but if anyone has bad experiences to share I might just cut my losses and clean up and reuse the factory cover.

Thanks!

Although I was using enhanced diff covers back in the racing days, towing was never on MY radar as a necessary option.
There is a wonderful video on You Tube where Gayle Banks does a clinic on the what, the how, and the why of a proper aftermarket diff cover.

I'd recommend watching it.

What aftermarket diff cover guys don't tell you!

Aftermarket rear differential covers have been around for decades. But what effect do they have on your gear oil? What's really going on behind the cover? Ga...

www.youtube.com

 

[mikeru]

Although I was using enhanced diff covers back in the racing days, towing was never on MY radar as a necessary option.
There is a wonderful video on You Tube where Gayle Banks does a clinic on the what, the how, and the why of a proper aftermarket diff cover.

I'd recommend watching it.

What aftermarket diff cover guys don't tell you!

Aftermarket rear differential covers have been around for decades. But what effect do they have on your gear oil? What's really going on behind the cover? Ga...

www.youtube.com

I watched a similar video he made a few years ago. I'm not a fluid dynamics expert, and what he's saying makes sense but Gale Banks' videos are definitely biased towards his products. Doesn't make him wrong though LOL. I think his video hitting back at Pedal Commander is hilarious.

 

[Sherman Bird]

I watched a similar video he made a few years ago. I'm not a fluid dynamics expert, and what he's saying makes sense but Gale Banks' videos are definitely biased towards his products. Doesn't make him wrong though LOL. I think his video hitting back at Pedal Commander is hilarious.

Yeah, you are accurate in that Mr. Banks has faults, as do we all. I'm NOT his advocate, nor do I have any vested interest in mentioning him. He DOES, however know what he is talking about. Me personally? I do not stray from stock in most bone-stock designs, simply because the factory infrastructure is typically good for the vast majority of we commoners need.

Back in the day when I participated in drag racing, these getty-up-go, super duper differential girdle springs, byrillium phosphoturbo canootin' valve thingamajigs and so forth were touted as necessary, and sometimes helped.

People are going to form beliefs and foster attitudes based on a wide variety of inputs from glossy full page ads in HotRod, what is or was on neighbor Gus's 440 tripower challenger, to the loud mouthed bench racer at the local speed shop.

I spent a lot of money in those days that made me "feel" that this gadget was going to make my car faster.

As my mentor in the automotive repair profession preached me over 50 years ago: "There are many things meant to be sold, not necessarily to buy".

I have never seen an independent engineer-based field test on a stock vehicle of these expensive differential covers. Come to think about it, most stock differentials last for the life of the vehicle, with a little maintenance.

A vast majority of the times I HAVE witnessed catastrophic failures, it was due to abuse. Trying to squeeze 3 pounds of umf from a 1 pound item.

 

[Kickboxer]

Its simple, put the OE cover back on. And do it right.

 

[BlackSheepRebel]

Although I was using enhanced diff covers back in the racing days, towing was never on MY radar as a necessary option.
There is a wonderful video on You Tube where Gayle Banks does a clinic on the what, the how, and the why of a proper aftermarket diff cover.

I'd recommend watching it.

What aftermarket diff cover guys don't tell you!

Aftermarket rear differential covers have been around for decades. But what effect do they have on your gear oil? What's really going on behind the cover? Ga...

www.youtube.com

wow, thanks for for all the responses... i expected this would generate some vitriol similar to every diff cover thread. sorry for the heartburn lol. i went back and forth on this one many times, and finally decided it would be fun since i was under there any way.

watched the banks video many times... it's circulated in every diff cover thread since it was published, and is the reason i chose one with a rounded back. love banks' approach in general, and overall feel his advice is sound engineering, but worth noting he makes a diff cover (just not for our trucks) and is a good salesman like any company owner needs to be.

interesting perspectives on torque... i torqued it because the manufacturer said to. maybe the torque spec is wrong in the docs...but many people install them at that torque, so more likely machining or tool issue. i don't buy snapon tools (if i was a professional mechanic i would), but it's not $5 china crap either...and torqued other cap screws fine. who knows. honestly hate allens for this reason.

good life lesson to learn (wrenching is a hobby vs trade for me, so plenty of these on each vehicle), finger-tighten anything allen (especially in aluminum), then look for drips and go a bit more if it leaks. my dad was a machinist and welder and warned many times about over-tightening, but i suspended my brain and just went with the docs.

mostly wanted magnetic drain plug, dislike messing with the rubberized fill plug, and enjoy the look... definitely not thinking it's way better, just different in ways i like. many people do personal preference mods, sort of like catback with no headers/pos-y-pipe. not upset about it, part of #modlife.

thanks for all the replies!

 

[RLee276]

Sounds like you used the wrong size Allen.

No need for a torque wrench on a drain plug.